Attachment for drawing-boards.



E. E. BARNARD.

ATTACHMENT FOR DRAWING BOARDS.

APPLICATION FILED IAN.25, 1912.

1, 1 39,0 1 1 Patented. May 11, 1915.

2 SHEETSSHEET 1.

fiZmerEBarmmj WHMMM A THE NORRIS PETERS C0" PHOTO-LITHQ. WASHINGTON, D. t

E. E. BARNARD.

ATTACHMENT FOR DRAWING BOARDS.

APPLICATION FILED 1AN.25. 1912.

1,139.01 1 Patented May 11, 1915.

2 SHEETSSHEET V2.

I 24771267" ZiBammi wi tmmoeo THE NORRIS PETERS C0.. FH070-LITHO., WASHINGTON, D. c 7

ELMER E. BARNARD, OF LYNCI-IBURG, VIRGINIA.

' 7 ATTACHMENT FOR DRAWING-BOARDS.

Specification of Letters Patent.

Patented May 11, 1915.

Application filed January 25, 1912. Serial No. 673,419.

readily attached to or removed from the board, the said arm having its extremity provided with an eye whereby the board may be suspended from a suitable hook when not in use, the arm being adapted to receive the point of a compass when a comparatively large segment of a circle is to bedescribed upon the board, or when it is desired to find the center of a circle, of say, known radii throughtwo' known points, by the intersecting method when the board is not large enough to receive the pivot point of the compass.

I further aim to provide a detachable arm for drawing boards which may be pivotally connected thereto and whereby the arm may be swung to describe various arcs of a circle, and whereby the said arm may be swung against the side of the board when not employed.

With the foregoing objects and others of a similar nature in view, the invention resides in the novel construction, combination and arrangement of parts set forth in and falling within the scope of theappended claims.

In the drawings, Figure 1 is a perspective view of a drawing board showing my improvement attached thereto. Fig. 2 is a similar view of the improvement. Fig. 3 is a detail bottom plan view of the attaching end of the improvement. Fig. 4 is a side elevation of the attaching clamp. Fig. '5 is a longitudinal sectional view taken through a drawing board provided with a modified form of my attachment. Fig. 6 is a top plan view of a still further modified form of my attachment. Fig. 7 is a sec tional view upon the line 77 of Fig. 6.

Referring now to the drawings in detail and to the showing illustrated in Figs. 1 to 4 inclusive, the numeral 1 designates an ordinary drawing board, thesame being provided with the usual spaced cleats 2. The numeral 3 designates my improved attachment. This attachment comprises an arm 4 which is adapted to lie in a plane flush with the upper face of the board and which is arranged at an angle to the board.

The arm t isprovided with an attaching element or clamp 5. The clamp comprises a bottom plate 6 which is provided with openings for the reception of securing elements 7. This bottom plate is let into a recess provided in the bottom face of the arm. The inner face of the plate, adjacent the opposite edges thereof is formed with angular extensions 8, the same having their upper extremities provided at right angles thereto with spaced fingers 9. In the said figures of the drawings the under faces of these fingers are roughened as designated by the numeral 10 to provide means whereby the fingers will bite into the board when the arm 4 is attached to the board and thus prevent the accidental movement of the said arm with relation to the board. The bottom plate 6 is centrally provided with a downwardly projecting portion 11, the same being intermediate of the extensions 8. and this portion 11 is provided with an angular longitudinally extending member 12, the same, of course, being arranged below and between the spaced fingers 9. The numeral 13 designates a rib which connects the members 11. and 12 and the plate 6 to provide a reinforcement for the said members 11 and 12. The member'12 is centrally provided with a threaded'opening for the reception of a screw 14, which has its lower extremity provided with a milled head 15. The opposite extremity of the-screw is provided with a swiveled head 16. and the upper face of this head is serrated or roughened as at 17.

By providing the clamp with the screw 15 it will be noted that the arm 4: may be attached to boards of various thicknesses. The arm 4, as heretofore set forth is arranged at a right angle to the board and sion or continuation of a line that has been drawn on the paper attached to the board. The fingers 9 have their upper extremities substantially flattened so ,as to ofi'er little or no obstruction to the T-square which is used upon the board, and the space between the fingers may be employed for the reception of the point of a compass when the sector of the circle to be described upon the board is of insufiicient circumference to necessitate the point being arranged upon the arm 4. The extremity of the arm 4 is pro vided with an eye 19, the latter serving as means whereby the board as well as the arm which is attached to the board may be suspended from a support when the board is not in use. This is highly desirable when unfinished work is left upon the board, and when the arm is positioned upon the board in a proper relation to the said work. When it is found desirable to remove the arm from the board, before the work upon the board has been completed, a small pencil line may be drawn upon the board in a plane parallel with .the line 18, the said pencil line serving as a guide and whereby the arm may be accurately repositioned upon the board.

In Fig. 5 of the drawings I have illustrated a slightly modified form of the clamp. In this figure the clamp is provided with the upper spaced fingers, which are designated by the numeral 9, only one, however, of the said fingers being shown. Each of the fingers 9 has its under face formed with a depression or pocket Within which is arranged a compressible member, such as a block of rubber 20. The clamp is provided with a lower finger which is arranged intermediate of the fingers 9, the said lower finger being provided with the threaded retaining element. The base plate 6 is horizontally straight and is arranged at an angle to the upwardly extending portion of the clamp so as to provide a right angular seat for the end of the arm 22. The plate 6 extends a suitabledistance beyond its reinforcing rib, the said extending portion being provided with an opening for the reception of a headed bolt 21. The numeral 23 designates a milled nut which is adapted to en-' gage the threaded extending portion of the bolt 21. The .bore or passage for the bolt provided upon the arm 22 is reamed adjacent the upper face of the said arm and whereby the head of the bolt may beretained flush with or slightly below'the said upper face of the arm. By an arrangement, as just described, it will be noted that various sizes of arms may be removably attached to the clamp, and also, if desired a' second board may be thus attached to the board 1. Furthermore, the horizontally straight plate 6 and its angular projecting wall provides means whereby the arm 22 is effectively seated and retained at a right angle to the board 1.

In Figs. 6 and 7 I have illustrated a still further modified form of the improvement. In these figures the clamp is provided with the spaced upper fingers 25' and the lower intermediate finger 25, the engaging portions thus comprising a member which is substantially U-shaped in side elevation as are the clamps heretofore referred to. The fingers 25 are each provided with depressions or pockets for the reception of the compressible members 26. The connecting member 24 of the fingers 25 and 25 is arranged at an angle to the said fingers, and the finger 25 is provided with a threaded opening for the reception of a threaded headed member 35 which has its upper extremity provided with a swiveled head 36 and which is adapted to engage with the under face of a board 37. The clamp is provided with a rounded head 27 which extends forward of the fingers 25 and which is arranged in a plane parallel to the said fingers. The head 27 has its upper portion at its periphery depressed to provide a substantially semi-cylindrical flange or lip 28.

The rounded head 27 is centrally provided with an opening which is adapted to receive a headed threaded member 29, and this member 29 is adapted to pass through an opening provided adjacent one end of a plate 30, the said threaded element being engaged and retained upon the head through the medium of a thumb screw 31. The plate 30 is provided with an upstanding or ofiset portion 32, the same being provided with an extending lip 33 and this lip is adapted to rest upon the flange 28 of the head 27. The edge of the lip 33 adjacent the head 27 is curved or rounded to agree with the rounded periphery of the said head, and the said rounded edge of the lip 33 is adapted to snugly engage the periphery of the rounded head 27 The reduced portion of the plate 30 which extends beyond the projection 32 thereof is provided with suitable openings, the same being adapted for the reception of securing elements, such as screws 38, and

'whereby an. arm 34 is retained upon the plate 30. The arm 34 as well as the upper face of the projection 32 andthe lip 33'provided thereby have a central longitudinally extending mark or line 40, while the head 24: is provided with graduations 41 which indicate the degrees of a circle. By this arrangement it will be noted that as the arm 34: is swung upon its pivot 29 the line 40 may be brought to register with any of the degree marks 41, and the angle of the arm 34 with relation to the board 37 may be thus readily ascertained.

From the above description, taken in connection with the'accompanying drawings the simplicity as well as the advantages of my improvement will, it is thought, be perfectly apparent to those skilled in the art without further detailed description, it may, however, be stated that the detachable arm may be employed as a rest for the arm of a draftsman whenlettering or markings are to be inscribed upon the paper on the board adjacent the margin thereof, which relieves the fingers of the draftsman from strain and which obviates the necessity of a rest for V the Wrist as Well as the possible necessity of removing the paper from the board to aced with the drawing board, said clamp being provided with an offset rounded head, the said head having its lower face provided with a rounded flange, a plate connected with the underface of the arm, said plate beingprovided with an upset portion having an extending lip which is adapted to engage with the flange of the clamp, an adjustable pivotal connection between the head of the clamp and the plate, the upset portion of the plate and the arm being provided with a longitudinally extending line, and the rounded head of the clamp being provided with graduation marks, substantially as and for the purpose set forth.

In testimony whereof I afiix my signature in presence of two witnesses.

ELMER E. BARNARD.

Witnesses WM. J. KOERTH, BURNETT S. Jonas.

G'opies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. G. 

